I wanted to correct a few facts.
First, while it has been reported that Registry pre-registered 5,000 domains this is incorrect. We have not registered the sites you mentioned. You can check the whois and look up the owners.
Second, The pricing referenced is out of date and not accurate. Prices can be found as low as $5 for a .feedback domain. Check out Crazydomains.com
Well, that's fine then. It's totally ethical to fleece people as long as you're not fleecing them /too much/.
If StackOverflow did actually register stackoverflow.feedback I would understand the WHOIS data, but then I don't understand the purpose of the following disclaimer:
"Disclaimer: This site is provided to facilitate free speech regarding Stack Overflow. No direct endorsement or association should be conferred."
That disclaimer seems to imply that StackOverflow didn't register the domain. Care to explain why the WHOIS data says otherwise?